The modulatory role of sulfated and non-sulfated small molecule heparan sulfate-glycomimetics in endothelial dysfunction: absolute structural clarification, molecular docking and simulated dynamics, SAR analyses and ADMET studies.

The conceptual technology of small molecule glycomimetics, exemplified by compounds C1-4, has shown promising protective effects against lipid-induced endothelial dysfunction, restorative effects on diabetic endothelial colony forming cells, and preventative effects on downstream vascular calcification amongst other important in vitro and ex vivo studies. We report the optimised synthesis of an array of 17 small molecule glycomimetics, including the regio-, enantio- and diastereo-meric sulfated scaffolds of a hit structure along with novel desulfated examples. For the first time, the absolute stereochemical configurations of C1-4 have been clarified based on an identified and consistent anomaly with the Sharpless asymmetric dihydroxylation reaction. We have investigated the role and importance of sulfation pattern, location, regioisomers, and spatial orientation of distal sulfate groups on the modulation of endothelial dysfunction through their interaction with hepatocyte growth factor (HGF). In silico studies demonstrated the key interactions the persulfated glycomimetics make with HGF and revealed the importance of both sulfate density and positioning (both point chirality and vector) to biological activity. In vitro biological data of the most efficient binding motifs, along with desulfated comparators, support the modulatory effects of sulfated small molecule glycomimetics in the downstream signaling cascade of endothelial dysfunction. In vitro absorption, distribution, metabolism, elimination and toxicity (ADMET) data demonstrate the glycomimetic approach to be a promising approach for hit-to-lead studies.

A Sulfuryl Group Transfer Strategy to Selectively Prepare Sulfated Steroids and Isotopically Labelled Derivatives.

The treatment of common steroids: estrone, estradiol, cortisol, and pregnenolone with tributylsulfoammonium betaine (TBSAB) provides a convenient chemoselective conversion of the steroids alcohol/phenol moiety to the corresponding steroidal organosulfate. An important feature of the disclosed methodology is the millimolar scale of the reaction, and the isolation of the corresponding steroid sulfates as their biologically relevant sodium salts without the need for ion-exchange chromatography. The scope of the method was further explored in the estradiol and pregnanediol steroid systems with the bis-sulfated derivatives. Ultimately, a method to install an isotopic label, deuterium (2H) combined with estrone sulfation is a valuable tool for its mass-spectrometric quantification in biological studies.

Chemical Methods for N- and O-Sulfation of Small Molecules, Amino Acids and Peptides.

Sulfation of the amino acid residues of proteins is a significant post-translational modification, the functions of which are yet to be fully understood. Current sulfation methods are limited mainly to O-tyrosine (sY), which requires negatively charged species around the desired amino acid residue and a specific sulfotransferase enzyme. Alternatively, for solid-phase peptide synthesis, a de novo protected sY is required. Therefore, synthetic routes that go beyond O-sulfation are required. We have developed a novel route to N-sulfamation and can dial-in/out O-sulfation (without S-sulfurothiolation), mimicking the initiation step of the ping-pong sulfation mechanism identified in structural biology. This rapid, low-temperature and non-racemising method is applicable to a range of amines, amides, amino acids, and peptide sequences.

Sulfation made simple: a strategy for synthesising sulfated molecules.

The study of organosulfates is a burgeoning area in biology, yet there are significant challenges with their synthesis. We report the development of a tributylsulfoammonium betaine as a high yielding route to organosulfates. The optimised reaction conditions were interrogated with a diverse range of alcohols, including natural products and amino acids.